The present invention relates to a handling robot in a multiple chamber type manufacturing system such as a semiconductor manufacturing system and an LCD manufacturing system, in which a plurality of process chambers are disposed around a single transfer chamber to constitute a like plurality of stations, and in which a workpiece in the form of a thin plate such as a wafer that is to be machined and processed in each of the process chambers is conveyed by the handling robot that is arranged in the transfer chamber, via the transfer chamber from one of the process chambers to another.
A multiple chamber type semiconductor manufacturing system is constructed as shown in FIG. 1 of the drawings attached hereto and has a plurality of process chamber stations 2a, 2b, 2c, 2d and 2e disposed around a transfer chamber 1 and also has arranged therein a pair of workpiece delivery stations 3 by each of which the workpiece is delivered to an outside thereof, and in which the space within the transfer chamber 1 is kept in an evacuated state by a suction unit.
And, the above mentioned transfer chamber 1 is constructed as shown in FIG. 2 of the drawings attached hereto and has a handling robot A provided at a central region thereof so as to be rotatable. It is also provided with a plurality of partition walls 5 that serve as the peripheral walls thereof with each wall opposing to each of the process chamber stations 2a, 2b, 2c, 2d and 2e and the workpiece delivery stations 3 and in which there are also provided a plurality of gates 6 each of which constitutes both an inlet and an outlet for the workpiece to be fed into and out of each of the stations. Each such gate 6 is configured so as to be opened and closed by an opening and closing door (not shown) that is disposed in opposition to each of the gates 6 in the transfer chamber 1.
As a conventional handling robot of this sort that has been used with a semiconductor manufacturing equipment, there has hitherto been known a handling robot A of so called flog leg type with a pair of arms as shown in FIGS. 3 to 11 of the drawings attached hereto and a handling robot Axe2x80x2 (see Japanese Unexamined Patent Publication No. Hei 7-227777) of identically directed operating type as shown in FIGS. 12 to 13B of the drawings attached hereto.
The above mentioned handling robot A of flog leg type with a pair of arms in the prior art is constructed as shown in FIGS. 3 to 6B.
In this construction, a boss section B is provided with the pair of arms, designated at 7a and 7b, of an identical length, which are arranged so as to be rotatable about a center of rotation. On the other hand, there are provided a pair of transfer tables 8a and 8b that have their respective bases, to each of which is connected one end of each of a pair of links 9a and 9b of an identical length, respectively. The one end of each of the both links 9a and 9b is coupled via a flog leg type transfer table attitude regulating mechanism to each of the transfer tables 8a and 8b, respectively, so that the two links 9a and 9b may be rotated in a pair of mutually opposite directions which are completely symmetrical with respect to the transfer tables 8a and 8b. And, one of the pair of links 9a and 9b which are coupled to the transfer tables 8a and 8b is pivotally coupled to one of the pair of arms 7a and 7b whereas the other of the links 9a and 9b is pivotally coupled to the other of the arms 7a and 7b, respectively.
FIGS. 4A and 4B in the drawings attached hereto show the transfer table attitude regulating mechanism of the above mentioned flog leg type, in which the respective forward end portions of the links 9a and 9b in the pair which are coupled to the transfer tables 8a and 8b are coupled together in an interlocking configuration that, as shown in FIG. 4A of the drawings attached hereto, comprises a pair of gears 9c and 9c which mesh with each other so that the angles of attitude xcex8R and xcex8L of the links 9a and 9b with respect to the transfer tables 8a and 8b may always be identical to each other. This allows each of the transfer tables 8a and 8b to be always oriented in a radial direction and operated in the radial direction when each of the arms 7a and 7b is rotated. It should be noted, however, that the above mentioned interlocking configuration for the links 9a and 9b may make use of a crossed belting arrangement 9d as shown in FIG. 4B of the drawings attached hereto, in lieu of the above mentioned gear arrangement.
FIG. 5 of the drawings attached hereto shows a mechanism for permitting the above mentioned arms 7a and 7b to be rotated independently each other. The respective bases of the arms 7a and 7b are each configured in the form of a ring shaped boss and such ring shaped bosses 10a and 10b are configured so as to be coaxial about the center of rotation and to be rotatably supported with respect to the transfer chamber 1.
On the other hand, the ring shaped bosses 10a and 10b have a pair of disk shaped bosses 11a and 11b disposed therein, respectively, wherein the ring shaped boss 10a, 10b and the disk shaped boss 11a, 11b corresponding thereto are arranged so as to be coaxial with each other. Each pair of a ring shaped boss 10a, 10b and a disk shaped boss 11a, 11b corresponding thereto are magnetically coupled with a corresponding one of magnetic couplings 12a and 12b, respectively.
The above mentioned pair of the disk shaped bosses 11a and 11b have their respective rotary shafts 13a and 13b which are arranged so as to be coaxial with each other. The rotary shafts 13a and 13b are coupled to the output sections of a pair of motor units 14a and 14b, respectively, which are coaxial with the frame la of the transfer chamber 1 and are supported with their positions deviated in their axial direction.
The above mentioned motor units 14a and 14b have each integrally coupled thereto a motor 15 which comprises, for example, an AC servo motor and a speed reduction gear 16 with a large speed reduction ratio which comprises, for example, a Harmonic Drive (trade name, identically referred to hereinafter). Such reduction gears 16 and 16 have their output sections which are coupled to the respective bases of the rotary shafts 13a and 13b, respectively. And, since the space within the transfer chamber 1 in which the arms 7a and 7b are positioned is held in an evacuated state, there is provided a sealing partition 17 each between the ring shaped boss 10a and the disk shaped boss 11a and between the ring shaped boss 10b and the disk shaped boss 11b of the present arm rotary mechanism.
FIGS. 6A and 6B show an operation of the above mentioned handling robot A. As shown in FIG. 6A, when the two arms 7a and 7b are located at a pair of diametrically symmetrical positions, respectively, with respect to the center of rotation, the links 9a and 9b will be in a state in which they assume their most expanded rotary positions with respect to each of the transfer tables 8a and 8b so that the latter may both be displaced toward the center of rotation.
In this state, by rotating the two arms 7a and 7b in an identical direction, it can be seen that the two transfer tables 8a and 8b will be rotated about the center of rotation whilst maintaining the radial positions thereof. Also, by rotating the two arms 7a and 7b in the directions in which they may approach towards each other (or in the mutually opposite directions), from the state shown in FIG. 6A, it can be seen that one of the transfer tables 8a that is located at such a position that the angle made by the two arms 7a and 7b is reduced will be pushed by the links 9a and 9b so as to be operatively projected in its radially outward direction so that it may be thrusted into one of the above mentioned process chamber stations 2a, 2b, 2c, 2d, 2e and 3 which are disposed adjacent to the radially outward side with respect to the transfer chamber 1 as shown in FIG. 6B. At this point of time, whilst the other of the transfer tables will be displaced towards the center of rotation, it can be seen that its amount of displacement will be small because of an angle that is made between the arm 7a, 7b and link 9a, 9b. 
On the other hand, the latter handling robot Axe2x80x2 of identically directed operating type in the prior art is constructed as shown in FIG. 12 to FIG. 13B of the drawings attached hereto.
The handling robot Axe2x80x2 that is disposed within a transfer chamber has a cylindrical case 22 that is provided with a flange 24 at its upper end, and above the flange 24 there is provided a rotary table 23 such as to be rotatable and further displaceable vertically. And, a first driven shaft 25 is provided as projecting from the lower end surface of the rotary table 23 through the flange 24. And, the first driven shaft 25 is coupled to a first drive source 26 that is provided within the above mentioned case 22. Thus, the arrangement is so constructed that with the said drive source 26 operated to rotate the driven shaft 25, the said rotary table 23 may be rotated. Here, it should be noted that a drive source for vertically driving the rotary table is omitted from the illustration in the drawing.
The upper surface of the above mentioned rotary table 23 has the respective intermediate portions of a pair of first links 28a and 28b pivotally attached thereto. A pivotal section of one link 28a of the pair of links 28a and 28b has fastened thereto one end of a second driven shaft 29 that is provided as extending within the case 22. The other end of the second driven shaft 29 has coupled thereto a second drive source 30 that is also provided within the above mentioned case 22. Thus, the arrangement is so constructed that the one link 28a of the first pair of links 28a and 28b may be rotated via the second driven shaft 29 by the second drive source 30.
One end of each of the above mentioned pair of first links 28a and 28b has coupled thereto the corresponding one of a pair of second links 32a and 32b which are configured so as to be rotatable via a pair of second bearing shafts 31a and 31b, respectively. And, the forward ends of the pair of second links 32a and 32b have a first fork-like transfer table 8axe2x80x2 coupled thereto.
Also, the other end of each of the above mentioned first links 28a and 28b has coupled thereto a corresponding one of a pair of third links 35a and 35b which are configured so as to be rotatable via a pair of third bearing shafts 34a and 34b. And, the pair of third links 35a and 35b have at their forward ends a second fork-like transfer table 8bxe2x80x2 coupled thereto.
And, whilst the above mentioned second bearing shaft 31a is configured so as to be rotatable with respect to the first link 28a and to be integral with the second link 32a, the above mentioned second bearing shaft 31b is configured so as to be integral with the first link 28b and to be rotatable with respect to the second link 32b. Also, whilst the third bearing shaft 34a is configured so as to be rotatable with respect to the first link 28a and to be integral with the said third link 35a, the above mentioned third bearing shaft 34b is configured so as to be integral with the first link 28b and to be rotatable with respect to the third link 35b. 
The above mentioned two transfer tables 8axe2x80x2 and 8bxe2x80x2 are deviated in position in a vertical direction and the first transfer table 8axe2x80x2 is displaced from the state shown in FIG. 12 in a retracting direction such that when the second transfer table 8bxe2x80x2 is displaced in an advancing direction they may not interfere with each other. And, the two transfer tables 8axe2x80x2 and 8bxe2x80x2 are then configured so as to be crossed in a state in which they are stacked one upon another vertically.
Each of the above mentioned bearing shafts 31a and 31b are projected at the lower sides of the first links 28a and 28b, respectively, and such projecting portions have fastened thereto a pair of second gears 36a and 36b which have an identical number of teeth. Also, each of the third bearing shafts 34a and 34b is projected towards each of the first links 28a and 28b, respectively and such projecting portions have fastened thereto, as shown in FIG. 13, a pair of third gears 37a and 37b which have an identical number of teeth, respectively. It should be noted that these pairs of gears, 36a and 36b; and 37a and 37b, respectively constitute synchronous mechanisms 38a and 38b. 
The above mentioned two synchronous mechanisms 38a and 38b will enable one link 28a of the pair of first links 28a and 28b to be rotated in the direction of normal rotation or reverse rotation by the drive source 30 via the second driven shaft 29. The rotation will then be transmitted via the first and second synchronous mechanisms 38a and 38b to the other link 28b of the first links 28a and 28b and the second links 32a and 32b as well as to the third links 35a and 35b to cause the pair of transfer tables 8axe2x80x2 and 8bxe2x80x2 to operatively be projected and retracted in an identical direction as shown in FIGS. 13A and 13B of the drawings attached hereto.
It may be noted at this point that the above mentioned conventional two handling robots A and Axe2x80x2 have each been expected to provide a functional effect as a two arm robot by virtue of the advantage that a pair of transfer tables are provided and can alternately or consecutively be used for each of a variety of stations. It has been found, however, that as a matter of reality there arises following problems.
More specifically, since a process order has been determined, it should be noted that where a wafer that has been processed in a process chamber station is successively transferred to a series of the succeeding stations, each of these stations contains a wafer that is being or that has been processed. Then, if a wafer that has been processed within a given station is exchanged with an unprocessed wafer therein, what the above mentioned former handling robot A in the prior art does is first to support an unprocessed wafer W1 on one of the transfer tables 8a and then to turn the handling robot A so as to oppose the other vacant transfer table 8b to the station 2e where the wafers are to be exchanged with each other (see FIG. 7).
Then, it will project the vacant transfer table 8b into the station 2e and receive a processed wafer W2 thereon (FIG. 8) to convey it into the transfer chamber 1. Thereafter, the handling robot A will be turned by 180xc2x0 (FIG. 9) to oppose the transfer table 8a supporting the unprocessed wafer W1 to the above mentioned station 2e and will then operatively project it into the station 2e (FIG. 10) and to convey the said unprocessed wafer W1 into the station 2e. The transfer table 8a that has then become vacant will be operatively retracted into the transfer chamber 1 (FIG. 11).
In this way, with the former handling robot A in the prior art, the problem has been encountered that each time a wafer is exchanged for a given station, it has to be turned by 180xc2x0 thus prolonging the cycle time for each individual wafer exchanging operation.
On the other hand, if the latter handling robot Axe2x80x2 in the prior art is adopted, it can be seen that since the two transfer tables 8axe2x80x2 and 8bxe2x80x2 are configured so as to be operatively projected and retracted in an identical direction, not only can a given workpiece be conveyed into a given process chamber but another workpiece can be conveyed out thereof while the handling robot Axe2x80x2 remains deactuated. Whilst with the handling robot Axe2x80x2 there is thus the advantage that the cycle time for conveying a workpiece into and out of a process chamber can be reduced and the projecting/retracting operation for each of the two transfer tables 8axe2x80x2 and 8bxe2x80x2 can be carried out with a single drive source or a small number of drive sources, not the feature that is lacking with the former handling robot A in the prior art, it has been found, however, that there have arisen there the problems which are mentioned below.
Specifically, inasmuch as the said handling robot Axe2x80x2 allows the state in which the two transfer tables are stacked one upon another vertically at an identical position to be projected and retracted each time the transfer operation is performed, there has always been a fear that a dust that had deposited upon the upper transfer table might fall onto the upper surface of a workpiece that was held on the lower transfer table, thus contaminating a surface of the lower workpiece.
Also, the two transfer tables being deviated in position vertically, the lacking of a vertical displacement feature will, if those transfer tables are alternately projected and retracted without moving vertically, cause the width of a vertical aperture of the gate to be enlarged by the amount of vertical deviation of the transfer tables with an unfavorable result with respect to an air tight retention of such a gate portion. For this reason, the above mentioned handling robot Axe2x80x2 of an identically directed operating type in the prior art has involved the problem that it requires a vertical displacement mechanism to be provided, thus complicating its structure for this provisioning. Also, when a workpiece is delivered onto a workpiece supporting table in a process chamber, it has been necessary that at least one transfer table should be moved vertically a distance by which it has been deviated in a vertical direction. Thus, an additional process step has been required and this has been an undesirable obstruction for the cycle time of a workpiece input and output conveyance to be reduced.
Accordingly, the present invention has been made with the foregoing problems taken into account, and has for its generic object to provide a handling robot that needs not to be turned at all or may be turned with a small angle in the order of 45xc2x0 for a given process chamber, to enable a wafer that has been processed within a station and a wafer unprocessed within a transfer chamber to be exchanged with each other. It is also a further object of the present invention to provide a handling robot whereby a dust dispersed from one transfer table may not fall onto both transfer tables and yet a vertical displacement mechanism is not required, without moving the entire robot vertically the width of a gate in a vertical direction can only be for a single transfer table, a minimum number of simplified mechanisms can only be included, the air tight feature of a gate portion gives a performance substantially equal to the said former type in the prior art and at the same time the cycle time for a workpiece input and output conveyance can be substantially reduced.
In order to achieve the object mentioned above, there is provided in accordance with the present invention, in a certain aspect thereof, a handling robot, which comprises a first and a second robotic link mechanism which are so configured as to be jointly rotatable, each robotic link mechanism having a transfer table at a forward end thereof to mount a workpiece and adapted to operatively be projected and retracted in a radial direction of the transfer table when they operatively extended and contracted, and in which the first and second robotic link mechanisms are arranged so that the two transfer tables may be located in a narrow angular range.
At this point it should be noted that when one of the robotic link mechanisms is operatively projected, the other robotic link mechanism will be operatively retracted. The above mentioned projecting operation will cause the transfer table to be projected from the transfer chamber into the process chamber station to deliver a workpiece mounted on the transfer table into the process chamber, or alternatively to receive a workpiece from the process chamber station. Also, the retracting operation will cause the transfer table to be retracted from the process chamber into the transfer chamber side. Also, the two robotic link mechanisms may be in a retracting state so as to be rotated in the transfer chamber.
According to the above mentioned construction, it is possible to alternate a projecting operation and a retracting operation for the first and second transfer tables within a narrow angular range, this causing a wafer that has been processed in a station and an unprocessed wafer in the transfer chamber to be exchanged with each other without turning the handling robot at all or by only slightly turning the same for a given station. This will allow the cycle time for exchanging the wafers with each other to be largely reduced.
In the construction mentioned above, each of the first and second robotic mechanisms comprises:
a plurality of bosses which may be rotated independently from each other;
a drive source respectively connected to each of the bosses;
two pairs of arms which are composed of one or two arms respectively provided for each of the bosses;
a pair of links coupled to each pair of such arms at forward ends thereof, respectively; and
the transfer tables coupled to the pair of links at forward ends thereof, respectively.
And also, in the construction mentioned above, it is preferred that there should be provided;
a first, a second and a third boss as aforesaid;
a first arm as aforesaid that is provided for the first boss on;
a second and a third arm as aforesaid which are provided for the second boss;
a fourth arm as aforesaid that is provided for third boss on a side surface thereof;
a first transfer table as aforesaid that is provided for the first and second arms at a forward end thereof via a pair of links; and
a second transfer table as aforesaid that is provided for the third and fourth arms at a forward end thereof via a pair of links.
In the construction mentioned above,
the first arm is radially directed and is provided for the first boss on a side surface thereof;
the second and third arms are radially directed and provided for the second boss on a side surface thereof so that they may be located at diametrically opposite sides of the second boss, respectively;
the fourth arm is radially directed and is provided for the third boss on a side surface thereof.
According to the preceding construction, it can be seen that with the first and second arms being rotated together in a direction in which they approach a side of the first transfer table that is coupled thereto via the links, the said first transfer table will be operatively projected. On the other hand, the third and fourth arms will then be rotated together in a direction in which they depart from the second transfer table that is coupled thereto via the links, this allowing the said second transfer table to be held in a retracted state.
In the above mentioned state, it can also be seen that with the third and fourth arms at this time being rotated together in a direction in which they approach the second transfer table that is coupled thereto via the links, the second transfer table will be operatively projected whilst the first transfer table on the contrary will be operatively retracted.
Also, in the above mentioned construction, it is preferred that there should be provided:
a first and a second boss as aforesaid;
a first and a second arms as aforesaid which are provided for the first boss;
a third and a fourth arms as aforesaid which are provided for the second boss;
a first transfer table as aforesaid that is provided for the first and fourth arms at a forward end thereof via the pair of links; and
a second transfer table as aforesaid that is provided for the second and third arms at a forward end thereof via the pair of links.
In the construction mentioned above,
the first and second arms are radially directed and are provided for the first boss on a side surface thereof so that they may be located at diametrically opposite sides of the first boss, respectively;
the third and fourth arms are radially directed and are provided for the second boss so that they may be located at diametrically opposite sides of the second boss, respectively, one of the third and fourth arms being provided on a surface of the second boss and the other of the third and fourth arms being located on a top surface of the second boss via an upstanding leg column.
And also, in the construction mentioned above,
the first and second arms are radially directed and are provided for the first boss on a surface thereof so that they may be located at diametrically opposite sides of the first boss, respectively;
the third and fourth arms are radially directed and provided for the second boss on a side surface thereof so that they may be located at diametrically opposite sides of the second boss, respectively.
According to the preceding construction, it can be seen that with the first and fourth arms being rotated together in a direction in which they approach a side of the the first transfer table that is coupled thereto via the the links, the said first transfer table will be operatively projected. On the other hand, the second and third arms will be rotated in a direction in which they depart from the second transfer table that is coupled thereto via the links, this allowing the second transfer table to be held in a retracted state.
In the above mentioned state, it can also be seen that with the second and third arms at this time being rotated together in a direction in which they approach the second transfer table via the said links, the second transfer table will be operatively projected whilst the first transfer table on the contrary will be operatively retracted.
Also, in the construction mentioned above, the first and second robotic link mechanisms can be arranged so that the two transfer tables may be stacked one above another vertically.
Also, the first and second robotic link mechanisms can be arranged so that the two transfer tables may not be stacked one above another vertically but may be deviated in position in a rotary direction thereof.
According to the preceding construction, it can be seen that since the transfer tables are not stacked one above another, even if a dust is dispersed from either of the transfer tables, there will be no contamination thereby of a wafer on the other transfer table. It should be noted at this point that whilst if a wafer is put into and out of a given station, the two robotic link mechanisms need to be rotated by an angle corresponding to an amount of deviation, the deviation, being in an order in which the two transfer tables are not stacked one upon another, will be slight.
Also, the construction mentioned above may be constituted of:
a rotary table;
a first drive source operatively connected to the rotary table;
a first and a second drive link mechanism supported by the rotary table so as to be each rotatable;
a second drive source operatively connected to one of the first and second drive link mechanisms;
a first and a second driven link mechanism, each having one end coupled to each of the first and second drive link mechanisms at a forward end thereof, respectively, so that they may be synchronously rotated following a rotation of each of the drive link mechanisms; and
a first and a second transfer table as aforesaid connected to the first and second driven link mechanisms, respectively.
According to the preceding construction, the first and second robotic link mechanisms will have their respective drive link mechanisms aforesaid rotate with a drive shaft so that the two transfer tables may be alternately projected and retracted via the driven link mechanisms. And, by causing the said rotary table to rotate with another drive source, the said two robotic mechanisms will be jointly rotated.
It should also be noted that any of said drive link mechanisms and the driven link mechanisms of the first and second robotic link mechanisms may be constituted by either a parallel link mechanism or a belt mechanism.
Also, in the construction mentioned above, it is preferable that the first and second robotic link mechanisms should be arranged so that the two transfer tables coupled respectively thereto may have an identical position in a vertical direction.
According to the preceding construction, it is advantageous that the projecting and retracting operation for the transfer tables by the first and second robotic link mechanisms is carried out at an identical position in a vertical direction. For this reason, not only is a vertical displacement mechanism required there but also this construction will enable the vertical width of a gate of the transfer chamber through which they are projected and retracted to be only for a single transfer table as aforesaid to enhance the air tightness of such a gate portion whilst simplifying the entire construction of the handling robot.